Solar-blind ultraviolet band-pass filter based on metal–dielectric multilayer structures

Solar-blind ultraviolet （UV） band-pass filter has significant value in many scientific, commercial, and military appli- cations, in which the detection of weak UV signal against a strong background of solar radiation is required. In this work, a solar-blind filter is designed based on the concept of ＂transparent metal＂. The filter consisting of Al/SiO2 multilayers could exhibit a high transmission in the solar-blind wavelength region and a wide stopband extending from near-ultraviolet to infrared wavelength range. The central wavelength, bandwidth, Q factor, and rejection ratio of the passband are numerically studied as a function of individual layer thickness and multilayer period.

Extra-narrowband metallic filters with an ultrathin single-layer metallic grating

Narrowband and high-transmission optical filters are extensively used in color display technology, optical information processing, and high-sensitive sensing. Because of large ohmic losses in metallic nanostructures, metallic filters usually exhibit low transmittances and broad bandwidths. By employing both strong field enhancements in metallic nano-slits and the Wood’s anomaly in a periodic metallic grating, an extra-narrowband and high-transmission metallic filter is numerically predicted in an ultrathin single-layer metallic grating. Simulation results show that the Wood’s anomaly in the ultrathin(thickness H = 60 nm) single-layer metallic grating results in large field enhancements in the substrate and low losses in the metallic grating. As a result, the transmission bandwidth(transmittance T > 60%) at λ = 1200 nm is as small as △λFWHM=1.6 nm, which is smaller than 4% of that in the previous thin dielectric and metallic filters. The corresponding quality factor is as high as Q = λ/△λFWHM= 750, which is 40 times greater than that in the previous reports. Moreover, the thickness of our metallic filter(H = 60 nm) is smaller than 40% of that in the previous reports, and its maximum transmittance can reach up to 80%. In experiments, a narrowband metallic filter with a bandwidth of about △λFWHM = 10 nm, which is smaller than 25% of that in the previous metallic filters, is demonstrated.

Essential metal Zn in sponge <i>Callyspongia aerizusa</i>from Spermonde Archipelago

Spermonde Archipelago has been found to have a high sponge biodiversity. Sponges that have feeding behavior as filter feeder can be exposed to heavy metals, including Zn metal. Zn is an essential metal that is physiologically needed by sponge to catalyze chemical reactions and generally operates on enzymes. A study on Zn pollution level in Spermonde Archipelago from zone I to Zone IV was conducted by analyzing Zn concentration in sponges, sediments, and seawater. Physicochemical parameters measurement in Spermonde Archipelago indicates that Spermonde Archipelago meets the requirements for sponge growth. Callyspongia aerizusa can be used as metal pollution indicator because this sponge can accumulate heavy metal Zn in high level (99.30 mg/kg dry weight). This sponge was derived from Kondingareng Lompo island at zone III. In addition, Kodingareng Lompo island waters had the highest Zn concentration compared to other islands. Sediments from Lae-Lae island at zone I had the highest Zn metal concentration. Lae-Lae island is the nearest island to Makassar coastal line.

A Novel Coating Method for Create Filter Media Capable to Remove Phosphate from Wastewater Effectively

Filtration materials coating with metallic oxides represented a good method for phosphate sorption. However, most of the researchers utilize chemicals as a source of metallic oxides and heating process to set the chemicals over the filtration materials. This study is aimed to introduce the furnace bottom ash FBA as a source of metallic oxides;it is available free because it is dumped as a waste material from power generation plants. The method of creating new filter media involves coating the limestone and sand by FBA, and the ordinary Portland cement OPC utilized as binder to binding the mixture materials. The water is the factor which is responsible for activating the OPC. All factors such as mixed materials ratio, water content and age of reaction have subjected to optimization process. The results revealed that the optimal mixture for phosphate removal consists of 40% FBA, 5% OPC from dry weight of supporting material, 35% water ratio from the total weight of FBA and OPC, and 14 days are enough to complete the materials reaction. Limestone-furnace bottom ash LFBA indicated high capacity for phosphate sorption and possibility of efficiency regenerate. This study demonstrates a new method for coating the filtration materials more convenient with sustainability approach.

Vision sensing of P-GMAW weld pool using narrow band filters with different center wavelengths

The selection of narrow band filter＇s center wavelength has an important influence on the quality of the weld pool image captured in passive vision mettmd for controlling arc welding process. In this paper, 29 narrow band filters with different center wavelengths ranging from ultraviolet to near infrared wavelength were used to capture images of weld pool during both the peak current period and the base current period of P-GMA W （ pulsed gas metal arc welding）. The experimental results showed that the filters with near infrared center wavelength could weaken the arc most during the peak current period, while during the base current period the entire weld pool could be seen with the filters with wavelength above 600 nm. The camera spectral response and the radio of arc to weld pool emission were considered to analyze the phenomenon of experimental results.

Treatment of tunnel wash waters-experiments with organic sorbent materials. PartⅡ: Removal of toxic metals

In the first part of the article, the column and the bag experiments concerning removal of polycyclic aromatic hydrocarbons (PAHs) and nonpolar oil (NPO) from tunnel wash waters using organic sorbent materials have been described. This part presents the results of removal of toxic metals. The metals of concern (Al, As, Cd, Cr, Cu, Fe, Pb, Mo, Ni, and Zn) were selected based on the priority toxicant pollutants defined in surface water quality criteria. Concentrations of these metals in the collected effluent...

Incidental echocardiographic finding:Fractured inferior vena cava filter

Inferior vena cava filters have gained increasing popularity in recent decades and knowledge on rare complications becomes vital to practicing physicians. A 30-year-old African American male with diabetes mellitus, hypertension, end-stage renal disease, history of deep venous thrombosis and placement of venacaval filter who was seen in the cardiology clinic for cardiac risks stratification prior to renal transplant. Patient denied any cardiac symptoms. A transthoracic echocardiogram was performed and showed two linear echoes bright densities in the right atrium and right ventricle embedded which was later found to be fractured filter struts by computed tomography. We discuss the various outcomes associated with nonretrieval of retrievable inferior vena cava filters.

耐辐照型纤维过滤器过滤性能的数值模拟

针对褶型金属纤维过滤器的过滤性能开展数值模拟研究,本文采用多孔介质模型,模拟金属纤维滤料内部复杂的堆积结构。根据纤维滤料的结构参数编写流动阻力和过滤效率计算程序,将该程序与FLUENT软件结合构成了金属纤维滤料过滤性能的数值模拟方法,并用实验数据验证了所建立模拟方法的准确性。利用此方法进一步研究了在不同进口流速下,大褶宽比矩形褶过滤器的过滤性能。结果表明:亚微米颗粒在低流速下通过高效过滤器,布朗扩散和拦截占主导作用,惯性碰撞可忽略不计;流量沿褶通道分配均匀,沿程阻力及局部阻力可忽略不计,总阻力等于介质阻力;相同褶宽条件下,随着进口流速的增加,最易穿透粒径逐渐减小。

地下金属矿山袋式除尘器捕尘材料研究现状及展望

袋式除尘器作为一种高效且适应性强的除尘设备而被广泛应用,但在地下金属矿山的实际应用中容易出现滤袋黏结,接口处易破坏及滤灰、清灰效果不佳等问题,且存在整体设备体积大、不易移动的弊端。研究重点从地下金属矿山环境特性,捕尘材料及其改良技术与评价标准进行阐述。结果表明:地下金属矿山作业环境及粉尘特性与其他工业场所差异较大;捕尘材料未来的主要研究方向为利用还原氧化石墨烯喷涂技术对PPS(聚苯硫醚)捕尘材料进行改良,以及研发适用于地下金属矿山的方法简单、成本低的新型可重复的袋式捕尘材料;进一步完善捕尘材料的综合性能及实际应用中的评价标准。研究为解决金属矿山粉尘问题提供了更为切实可行的方案。

金属长滤袋脉冲喷吹清灰均匀性优化研究

为了探究喷吹管的喷吹孔径分布方式对金属长滤袋脉冲喷吹清灰均匀性的影响,采用3种喷吹孔径分布方式不同的喷吹管对金属长滤袋进行脉冲喷吹实验,对比研究不同喷吹孔径分布方式下,沿喷吹管气流方向滤袋间侧壁压力峰值分布规律。结果表明:采用喷吹管T_(1)时,滤袋侧壁压力峰值沿喷吹孔K_(1)—K_(9)方向分布不均匀,波动幅度较大,不满足清灰均匀性的要求;采用喷吹管T_(2)时,滤袋清灰均匀性有所改善,但仍不满足清灰均匀性的要求;采用喷吹管T_(3),喷吹孔K_(1)—K_(9)对应滤袋侧壁压力峰值变化趋势平缓,各测点侧壁压力峰值的方差均小于0.01,表明喷吹管T_(3)满足金属长滤袋清灰均匀性的要求。结果表明可以采用改变喷吹管孔径及其分布方式提高金属长滤袋脉冲喷吹的清灰均匀性。

基于HMSIW的小型化三模带通滤波器设计

传统的多模谐振器引入多个谐振器,并利用其中两个甚至多个谐振模式来组合构建滤波器通带,但由于其谐振器个数较多而在射频系统中占用了较大的空间。为此,本文提出了基于半圆形半模基片集成波导(HMSIW)的三模带通滤波器,通过引入金属化过孔来扰动半圆形HMSIW谐振腔的谐振模式的电场分布,使得对应的谐振模式的频率也会随之发生偏移,进而使原本谐振频率相差较大的三个谐振模式的频率逐渐靠近,最终组合形成滤波器的通带。该设计无需引入额外的谐振器,能够实现滤波器尺寸减半甚至成倍减少,从而达成小型化的目的。

室内空气滤尘中主要重金属元素污染特征初探

采用电感耦合等离子体质谱法测定空气滤尘中22种金属元素含量,并分别用富集因子法及主成分分析法对对其统计分析。结果表明Mo、Ba、W等十四个金属元素为轻微富集,Hg、Tl、Bi等五个为重富集重金属元素,Ti为极重富集重金属元素。并由主成分分析知载荷值较高的金属元素分布与人们生活中液化天然气、家用电器、实验仪器的使用以及室内装修密切相关。由此本研究揭示了室内空气滤尘重金属污染来源,为室内空气重金属污染评价方法提供了参考。

过滤器自动反吹控制系统设计

过滤器是化工生产工艺中分离物料的关键设备,在上下游工艺中发挥着至关重要的作用。过滤器运行时物料易附着在滤芯上导致过滤面积减小,运行压差增大,因此需要及时清灰。通过PLC系统远程自动控制反吹阀对滤芯进行定阻清灰或定时清灰,确保过滤器持续有效地运行,并保证整个装置长周期稳定运行。

金属空气预过滤器在某核电站AC厂房的应用

根据某核电站AC厂房送风系统要求和框架文件设计了一种可复用的金属空气预过滤器,与核电站原空气预过滤器的安装方案和运行压差进行了对比。结果表明,运行相同时间后,金属空气预过滤器上游、下游压力和压差上升比例均低于原空气预过滤器,表明金属空气预过滤器运行更稳定。达到终阻力时,金属空气预过滤器可清洗后复用,有良好的应用前景。

异构脱蜡装置金属过滤器设计与试验研究

异构脱蜡装置原料蜡油过滤器易堵塞,再生效果差。将滤芯材料更换为高精度金属复合膜滤材,再生方式改为液体鼓泡+气体爆破反冲洗组合工艺系统,试验验证改进效果。结果表明,金属复合膜对蜡油中5μm以上金属颗粒的拦截效果超过98%,过滤后的蜡油固含量(质量分数)小于5×10^(-6),能够满足生产要求。经过多次循环反冲洗后,过滤器的初始压差和运行时间基本无变化,说明液体鼓泡+气体爆破反冲洗组合再生工艺应用效果良好。

滤膜中铅质控样品的研制

针对滤膜中铅质控样品,提出一种制备和定值方法。将混合纤维素空白滤膜作为基质,采用标准体积添加方式进行制备,再用火焰原子吸收分光光度法进行均匀性和稳定性评估,并进行不确定度评定。结果表明:该方法具有可行性,且样品的均匀性和稳定性较好,量值和不确定度符合使用要求,可为其检测方法及数据有效性的评价提供参考。

金属滤芯在冷轧干法除尘中的应用

随着环保意识的增强,国家对钢铁行业的污染物排放要求越来越高,旨在探讨金属滤芯在冷轧干法除尘中的应用。冷轧厂在生产过程中会产生大量扬尘,因此,需设置干法除尘净化设施。传统布袋干法除尘和塑烧板除尘均存在一定问题,如易“糊袋”、阻力上升快、能耗高等。结合金属滤芯在有色行业运行的效果,探索了其在冷轧厂干法除尘中的应用,并取得了良好效果。

基于正弦图融合的CT金属伪影校正算法研究

目的为解决修复后的投影数据与周围投影数据之间过渡不连续的问题,提出一种基于正弦图融合的CT金属伪影校正算法。方法通过预处理和K均值聚类技术将具有相同空间信息的组织聚在一起生成先验图像,并根据金属区域与先验图像的投影差异校正原始图像投影以得到校正后的投影数据,最后采用滤波反投影算法重建得到校正后的CT图像。结果在CT仿真数据验证中,基于先验插值的金属伪影校正(Fusion Prior-Based Metal Artifact Reduction,FP-MAR)算法在单金属校正和多金属校正中的峰值信噪比分别为0.943和0.915,比线性插值校正金属伪影(Linear Interpolation Based Metal Artifact Reduction,LI-MAR)算法分别增加了28.65%和44.55%;FP-MAR算法在单金属校正和多金属校正中的结构相似性分别为0.984和0.961,比LI-MAR算法分别增加了48.41%和64.27%。临床CT伪影影像验证中,FP-MAR算法校正后CT金属伪影的主观评价高于LI-MAR算法校正后的CT金属伪影图像,且二者差异有统计学意义。结论本研究提出的算法可有效解决修复后的投影数据与周围投影数据之间过渡不连续的问题,更好地保留金属结构附近的信息。

钛合金滤器异种金属接头密封及电绝缘问题研究

通过对钛合金滤器中异种金属接头安装部位的结构特点分析,根据异种金属电偶腐蚀原理,确定钛合金异种金属接头的电绝缘防护方案,经过分析目前主要有四种电绝缘防护方案,即表面氧化、陶瓷喷涂、非金属和非金属+表面氧化双重组合。通过对各种钛合金异种金属接头的电绝缘防护方案的原理结构分析,并通过各种电绝缘方案进行密性和电绝缘性能试验验证,发现表面氧化和陶瓷喷涂在经过多次拆装后,会出现电绝缘性能失效的情况;非金属方案的密封性能和电绝缘性能均满足使用要求;非金属+表面氧化双重组合采用双重电绝缘方案防护,提高了异种金属接头电绝缘性能的可靠性和使用寿命,为后续钛合金平肩接头的密封和电绝缘性能研究提供一定的经验积累。

基于固定污染源废气监测的玻璃纤维滤筒纯化试验研究

固定污染源是大气的重要污染源,重金属主要以颗粒物形式存在于固定污染源废气中。固定污染源废气监测通常使用玻璃纤维滤筒采集颗粒物样品,进而测定重金属含量。为降低玻璃纤维滤筒的重金属含量本底值,试验采用向硝酸中加入乙二胺四乙酸二钠(EDTA-Na_(2))的方法对滤筒进行纯化。结果表明,该方法纯化滤筒的精密度较好,可有效降低滤筒中铅、镍、铜、锰、锡、铍、汞、砷和锑的含量,提高玻璃纤维滤筒的应用价值。